The present invention relates to a sorter which is provided to an image forming apparatus such as a copier and printer to sort sheets discharged from the apparatus, and more particularly relates to a sorter having a plurality of bins, and the sorter is provided with a stapling device to staple the sheets in the bin.
For a sheet processing device provided with a stapling device to staple sheets discharged from a copier, printer and the like, a sheet finisher has been utilized which is installed together with an automatic recirculating document handler in order to staple the sheets. However, the aforementioned sheet finisher is disadvantageous because the structure is so complicated and expensive.
(1) In Japanese Patent Publication Open to Public Inspection no. 43457/1989, there has been disclosed an apparatus in which a stapling device is provided to a relatively simple bin-moving type of sorter. In the aforementioned apparatus, a stapling device to staple sheets discharged into a bin can be freely moved with regard to the bin.
(2) Another sorter is composed in such a manner that: a fixed type of stapling device is provided to each bin; and the bin is moved to the stapling position so that a bundle of sheets can be stapled.
(3) A sorter disclosed in the official gazette of Japanese Patent Publication Open to Public Inspection No. 244869/1987, includes: a bin having sheets is moved to a position where a stapling operation can be conducted; the sheets are stapled by a stapling device; and when the sheets in other bins are stapled, the stapling device is moved in a vertical direction.
In the aforementioned sorter of case (1) having a stapling device which can be moved freely, the moving stroke of the stapling device changes according to sheet size. Accordingly, when the vertical spacing of each bin is wide, the sorter size becomes large as a whole, and when the vertical spacing of a bin into which the stapling device is inserted, is extended, the mechanism becomes complicated. Further, this sorter is composed in such a manner that: a closed loop type of large slotted hole is formed in the bin; and a common alignment member is inserted into the aforementioned slotted hole so that the alignment member can be reciprocated. In this case, however, it takes time to assemble, overhaul and adjust the sorter because it is necessary to insert the aforementioned alignment member into the slotted hole after a plurality of bins have been assembled and further it is necessary to connect the alignment member with the upper and lower arms. Furthermore, in the case of a sorter in which sheets of different sizes are stacked in a bin as the center of the sheet agrees with the center of the bin, in which the bin is moved to a stapling position, the aforementioned slotted hole must be made large, so that this type of sorter is disadvantageous in that the size of the bin is extended.
In the aforementioned sorter of case (2), the structure of the sorter is complicated as a whole, and in the case where the vertical spacing of the bin is small, a special stapling device is required.
In the aforementioned sorter of case (3), each bin in which sheets are put, is moved straight along a bin guide at an appropriate time. Accordingly, it is disadvantageous in that the structure becomes complicated.